Thousands lit candles, visited mass graves and observed two minutes of silence ontoday two years after a tsunami pulverised villages along Indian Ocean shores and killed or left missing about 230,000 people.
At a mosque in Ulee Lheue, Aceh, the Indonesian province worst hit by monster waves that came rolling out of the sea on a bright Sunday morning, imam Usman Dodi told worshippers the tsunami was a religious warning.
"Please forgive the people who have left us for their wrongdoing," the imam prayed, returning to a sermon some religious leaders preached after a disaster that killed or left missing 169,000 people in northern Sumatra. Half a million were also made homeless.
The seaside mosque in Ulee Lheue became an icon of one of history's worst natural disasters.
It was the only building left standing after a magnitude 9.1 earthquake ruptured the ocean floor off the tip of northern Sumatra, triggering waves that slammed into the coastlines of a dozen Indian Ocean nations.
Former US Presidents Bill Clinton and George Bush visited the town and helped raise hundreds of thousands of dollars in rebuilding projects.